MIPS: qemu_mips: Import asm/unaligned.h from the Linux kernel

with a few adjustments for U-Boot.  This fixes the following build error:

make -C lib_generic/
zlib.c:31:27: error: asm/unaligned.h: No such file or directory
zlib.c: In function 'inflate_fast':
zlib.c:641: warning: implicit declaration of function 'get_unaligned'
make[1]: *** [zlib.o] Error 1
make[1]: Leaving directory `/home/skuribay/git/u-boot.git/lib_generic'
make: *** [lib_generic/libgeneric.a] Error 2

Reported-by: Himanshu Chauhan <himanshu@symmetricore.com>
Signed-off-by: Shinya Kuribayashi <skuribay@pobox.com>

include/asm-mips/unaligned.h

+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2007 Ralf Baechle (ralf@linux-mips.org)
+ */
+#ifndef _ASM_MIPS_UNALIGNED_H
+#define _ASM_MIPS_UNALIGNED_H
+
+#include <compiler.h>
+#if defined(__MIPSEB__)
+#define get_unaligned	__get_unaligned_be
+#define put_unaligned	__put_unaligned_be
+#elif defined(__MIPSEL__)
+#define get_unaligned	__get_unaligned_le
+#define put_unaligned	__put_unaligned_le
+#else
+#error "MIPS, but neither __MIPSEB__, nor __MIPSEL__???"
+#endif
+
+#include <linux/unaligned/le_byteshift.h>
+#include <linux/unaligned/be_byteshift.h>
+#include <linux/unaligned/generic.h>
+
+#endif /* _ASM_MIPS_UNALIGNED_H */